JP5878450B2 - Air-cooled oil cooler mounting structure for internal combustion engines - Google Patents

Description

  The present invention relates to an air-cooled oil cooler mounting structure for an internal combustion engine mounted on a vehicle.

An air-cooled oil cooler of an internal combustion engine mounted on a vehicle is attached to a place where traveling wind directly hits the outside of the internal combustion engine.
In Patent Document 1, an air-cooled oil cooler is attached to a down frame extending downward from a head pipe in a body frame of a motorcycle.

JP 2010-196564 A

  Since the air-cooled oil cooler disclosed in Patent Document 1 is attached to the down frame in front of the internal combustion engine, traveling wind directly hits without being affected by the heat of the internal combustion engine, and an oil cooling effect is expected by air cooling. it can.

  However, since the air-cooled oil cooler is separated from the internal combustion engine, an oil introduction pipe for introducing oil from the internal combustion engine and an oil outlet pipe for returning oil to the internal combustion engine are separately required. Must be concatenated.

  Therefore, in addition to the work of attaching the air-cooled oil cooler to the down frame, the work of connecting the oil introduction pipe and the oil lead-out pipe is required, and the number of parts is increased, requiring time and labor for the assembly work.

  In addition, there is a case where a space for mounting the air-cooled oil cooler cannot be secured because another member (for example, a radiator) is provided on the down frame, and it is necessary to consider another mounting position.

  The present invention has been made in view of the above points, and the object of the present invention is that the oil cooling effect can be greatly expected, and it can be assembled to an internal combustion engine without requiring an oil pipe and can be assembled with a small number of parts. It is in the point which provides the air cooling type oil cooler mounting structure of the internal combustion engine which was excellent.

In order to achieve the above object, the invention according to claim 1
In a vehicle-mounted internal combustion engine in which a crankcase cover (50) covers an axially outer side of a crankcase (11) that rotatably supports a crankshaft (20) oriented in the vehicle width direction,
An oil cooler unit (70) in which an air-cooled oil cooler (71) is integrally provided with an oil introduction passage (75i) and an oil delivery passage (76e), the oil introduction passage (75i) and the oil delivery passage (76e) are provided. wherein each communicates with the oil upstream passage formed in the crankcase cover (50) (58) and the oil downstream passage (59), mounted on a front portion of the crankcase cover (50),
The crankcase cover (50) is formed with a mating surface with the crankcase (11) on the outer peripheral edge of the cover side wall (51),
The air-cooled oil cooler (71) is positioned in front of the bulging wall (52) that bulges outward in the vehicle width direction of the cover side wall (51), and is wider than the bulging end of the bulging wall (52). Placed inside the direction,
The front outer surface (51s) of the cover side wall (51) in front of the bulging wall (52) and the front surface (52s) of the bulging wall (52) intersect each other at a substantially right angle and are lost in an L shape. A corner (57) is formed,
The air-cooled oil cooler (71) is disposed at the corner (57) in front of the bulging wall (52) of the cover side wall (51),
Mounting bosses (55, 56) are provided on the front surface (52s) of the bulging wall (52) or the front outer surface (51s) of the cover side wall (51), the oil upstream side passageway (58) and the oil downstream side. Projecting with passageway (59),
The unit mounting portion (75a, 76a) fixed to the mounting boss portion (55, 56) of the bulging wall (52) includes the oil introduction passage (75i) and the oil outlet passage (76e). Built integrally with the cooler unit (70),
By fixing the unit mounting portions (75a, 76a) of the oil cooler unit (70) to the mounting boss portions of the crankcase cover (50), the oil upstream passage (58) and the oil downstream passage The oil cooler unit (70) is attached to the crankcase cover (50) by connecting the oil introduction passage (75i) and the oil lead-out passage (76e) to (59), respectively. This is an air-cooled oil cooler mounting structure.

The invention according to claim 2
The air-cooled oil cooler mounting structure for an internal combustion engine according to claim 1,
The oil cooler unit (70) is attached to the front portion of the crankcase cover (50) in a posture in which the cooling fin (73) provided in the air-cooled oil cooler (71) faces the front of the vehicle body. And

The invention described in claim 3
In the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 1 or 2 ,
The front surface (52s) of the bulging wall (52) is inclined obliquely upward.

The invention according to claim 4
The air-cooled oil cooler mounting structure for an internal combustion engine according to any one of claims 1 to 3 ,
The oil cooler unit (70) is configured so that the air-cooled oil cooler (71) is positioned on the outer side in the vehicle width direction, the unit mounting portion (75a, 76a) is set on the inner side in the vehicle width direction, and the unit mounting portion (75a, 76a ) Is positioned along the front outer side surface (51s) of the cover side wall (51) and fixed to the mounting boss portion (55, 56) of the crankcase cover (50).

The invention according to claim 5
The air-cooled oil cooler mounting structure for an internal combustion engine according to any one of claims 1 to 4 ,
At least the front and the outer side in the vehicle width direction of the air-cooled oil cooler (71) are covered with a breathable protector (80).

The invention described in claim 6
The air-cooled oil cooler mounting structure for an internal combustion engine according to claim 5 ,
The protector (80) is attached to the crankcase cover (50) together with the oil cooler unit (70).

According to the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 1, the outer side in the axial direction of the crankcase (11) that rotatably supports the crankshaft (20) oriented in the vehicle width direction is connected to the crankcase cover ( 50), the oil cooler unit (70) in which the air cooling oil cooler (71) is integrally provided with the oil introduction passage (75i) and the oil outlet passage (76e) is provided with the oil introduction passage (75i). ) And the oil outlet passage (76e) communicate with an oil upstream passage (58) and an oil downstream passage (59) formed in the crankcase cover (50), respectively, and are connected to the front of the crankcase cover (50). Since the air-cooled oil cooler (71) attached to the front part of the crankcase cover (50) outside the vehicle width direction of the crankcase (11) of the internal combustion engine (10) is directly attached to the internal combustion engine Oil cooling effect because it is far from the heat source of (10) The air-cooled oil cooler (71) is assembled to the internal combustion engine (10) as an oil cooler unit (70) without the need for an external oil pipe, and assembly work can be performed with a small number of parts. Easy and easy to assemble.
The crankcase cover (50) has a mating surface with the crankcase (11) formed on the outer peripheral edge of the cover side wall (51), and the air-cooled oil cooler (71) is arranged in the vehicle width direction of the cover side wall (51). Since it is arranged in front of the bulging wall (52) bulging outward and inward in the vehicle width direction from the bulging end of the bulging wall, The air-cooled oil cooler (50) is installed using dead space, and the bulging wall (52) covering the back of the air-cooled oil cooler (50) over the entire vehicle width direction covers the air-cooled oil cooler (50). Can be protected from behind.
A corner portion where the front outer surface (51s) of the cover side wall (51) in front of the bulging wall (52) intersects the front surface (52s) of the bulging wall (52) at a substantially right angle and is missing in an L shape. (57) is formed, and the air-cooled oil cooler (71) is disposed at the corner (57) in front of the bulging wall (52) of the cover side wall (51), so that the crankcase cover (50) The air-cooled oil cooler (71) can be compactly housed in the corner (57), which is a dead space in front of the bulging wall (52), and the degree of freedom in equipment layout can be increased.
By attaching the unit mounting part (75a, 76a) of the oil cooler unit (70) to the mounting boss part (55, 56) of the crankcase cover (50), the oil upstream side passage (58) and the oil downstream side passage ( 59) is connected to the oil inlet passage (75i) and the oil outlet passage (76e), and the oil cooler unit (70) is attached to the crankcase cover (50), eliminating the need for external oil pipe piping. The number of parts is reduced, making assembly work extremely easy.

  According to the air-cooled oil cooler mounting structure of the internal combustion engine according to claim 2, the oil cooler unit (70) is in a posture in which the cooling fin (73) provided in the air-cooled oil cooler (71) faces the front of the vehicle body. Since it is attached to the front part of the crankcase cover (50), the traveling wind from the front of the vehicle body directly hits the cooling fin (73), and the oil circulating through the air-cooled oil cooler (71) can be efficiently cooled.

According to the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 3, since the front surface (52s) of the bulging wall (52) is inclined obliquely upward, the air-cooled oil cooler (71) is Since the cooling air after passing smoothly flows along the inclined surface of the front surface (52s) of the bulging wall (52), the oil can be efficiently cooled.
Further, the bulging wall (52) protects the back and bottom of the air-cooled oil cooler (71) and can protect the air-cooled oil cooler (71) from flying stones as much as possible.

According to the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 4 , the unit mounting portion (75a, 76a) is positioned on the inner side in the vehicle width direction along the front outer surface (51s) of the cover side wall (51). Therefore, the oil passage (58, 59) in the crankcase cover (50) can be set short, and the air-cooled oil cooler (71) is positioned outside the vehicle width direction to drive the air-cooled oil cooler (71). The oil can be efficiently exposed to the wind, and the oil cooling efficiency can be increased.

According to the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 5 , at least the front and the outer side in the vehicle width direction of the air-cooled oil cooler (71) are covered with the air-permeable protector (80). With (80), the air-cooled oil cooler (71) can be protected from external force without impairing the cooling effect of the air-cooled oil cooler (71) due to the traveling wind.

According to the air-cooled oil cooler mounting structure for an internal combustion engine according to claim 6 , since the protector (80) is attached to the crankcase cover (50) together with the oil cooler unit (70), the number of parts is reduced. Make assembly work even easier.

1 is a right side view of a motorcycle equipped with an internal combustion engine according to an embodiment of the present invention. It is a right view of the same internal combustion engine. FIG. 3 is a sectional view of the same internal combustion engine (a sectional view taken along line III-III in FIG. 2). It is a disassembled side view of a right crankcase cover, an oil cooler unit, and a protector. It is a front view of an oil cooler unit. It is a perspective view of a protector. It is a side view of the state which assembled | attached the oil cooler unit and the protector to the right crankcase cover. FIG. It is the same front view. It is the same top view. It is a side view of the state which assembled | attached the oil cooler unit and the protector to the right crankcase cover in another embodiment.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is an overall side view of a motorcycle 1 equipped with an internal combustion engine 10 according to the present embodiment.

The body frame 2 of the motorcycle 1 has a pair of left and right main frames 2b, 2b extending rearward from the head pipe 2a and then bent downward to form steeply inclined portions 2ba, 2ba. Is bent forward to reach the lower end.
Further, a pair of left and right down frames 2c, 2c are extended substantially parallel to the steeply inclined portion 2ba of the main frame 2b in a side view when viewed downward from the head pipe 2a.

  The seat rails 2d and 2d extend rearward from the upper portions of the steeply inclined portions 2ba and 2ba of the main frames 2b and 2b, and the back connecting the central portion of the seat rails 2d and 2d and the lower portion of the steeply inclined portions 2ba and 2ba. The stays 2e and 2e support the seat rails 2d and 2d.

In the vehicle body frame 2 as described above, the front fork 3 is pivotally supported on the head pipe 2a, the front wheel 4 is pivotally supported at the lower end thereof, and the front end is pivoted on the pivot plate 2f provided at the lower part of the main frames 2b and 2b. The supported rear fork 5 extends rearward, a rear wheel 6 is pivotally supported at the rear end thereof, and a rear cushion 7 is interposed between the rear portion of the rear fork 5 and the central portion of the seat rails 2d and 2d. .
A fuel tank 8 is installed on the main frames 2b and 2b, and a seat 9 is provided behind the fuel tank 8 and supported by seat rails 2d and 2d.

  The internal combustion engine 10 mounted on the vehicle body frame 2 is an SOHC type single-cylinder four-stroke internal combustion engine. The crankshaft 20 is oriented in the vehicle body width direction with respect to the vehicle body, and the cylinder is tilted slightly forward to stand upright. Suspended.

  The crankcase 11 that rotatably supports the crankshaft 20 of the internal combustion engine 10 is formed with a transmission chamber 11M that houses the transmission 40 behind the crankcase 11C in which the crankshaft 20 is disposed (see FIG. 3). Below the crank chamber 11C, a bottom wall bulges somewhat downward to form an oil sump 11P for storing oil (see FIGS. 2 and 3).

2 and 3, on the crank chamber 11C of the crankcase 11, a cylinder block 12 having one cylinder 12a and a cylinder head 13 are overlaid on the cylinder block 12 via a gasket. The cylinder head cover 14 covers the cylinder head 13 above the cylinder head 13.
The cylinder block 12, the cylinder head 13, and the cylinder head cover 14 stacked on the crankcase 11 extend upward from the crankcase 11 in a slightly tilted posture (see FIGS. 1 and 2).

  In this way, the intake pipe 101 extends rearward from the cylinder head 13 erected with the internal combustion engine 20 mounted on the vehicle body frame slightly tilted forward, and the intake pipe 101 is viewed from the side of the main frame through the throttle body 102. 2a, the seat rail 2d, and the air cleaner 103 disposed in a space surrounded by the backstay 2e (see FIG. 1).

  Further, the exhaust pipe 105 extending forward from the cylinder head 13 is bent downward and further bent rearward, and is disposed rearward along the lower surface of the crankcase 11 and on the right side of the rear wheel 6 toward the right side. It is connected to the muffler 106.

  The crankcase 11 coupled to the lower portion of the cylinder block 12 includes a left crankcase 11L, which is a pair of cases divided into left and right on a plane that includes the cylinder axis (center axis of the cylinder 12a) and is orthogonal to the crankshaft 20. The right crankcase 11R is configured by being mated with each other on the mating surfaces and coupled with bolts (see FIG. 3).

  The crankshaft 20 that is rotatably supported by the left and right crankcases 11L and 11R in the left-right direction is configured by integrally connecting the left and right crankshaft bodies 20L and 20R with crankpins 21 (see FIG. 3).

  Annular bearing bushes 22 and 22 are embedded in the outer periphery of the bearing walls 11Lw and 11Rw of the left and right crankcases 11L and 11R that support the crankshaft 20, and the inner periphery of the bearing bushes 22 and 22 is metal. The left and right crankshaft bodies 20L and 20R of the crankshaft 20 are pivotally supported via the bearings 23 and 23.

On the other hand, as shown in FIG. 3, the lower part of the cylinder 12a of the cylinder block 12 is fitted into a circular opening formed above the crank chamber 11C by combining the left and right crankcases 11L and 11R, and is inserted into the cylinder bore 12b of the cylinder 12a. The piston 16 is fitted so as to be slidable back and forth.
A piston pin 17 is installed between a pair of pin bosses that protrude from the back surface of the piston top of the piston 16, a small end is pivotally supported by the piston pin 17, and a large end is pivotally supported by the crankpin 21 of the crankshaft 20. The connecting rod 18 connects the piston 16 and the clan shaft 20 to constitute a crank mechanism.

  Corresponding to the cylinder 12a, the cylinder head 13 is provided with a combustion chamber 13b opposite to the piston 16 in the cylinder axial direction, and a spark plug 19 faces the combustion chamber 13b on the ceiling wall of the combustion chamber 13b. (See FIG. 3).

Referring to FIG. 3, the valve mechanism 60 is a valve mechanism of a SOHC type internal combustion engine in which one cam shaft 65 is pivotally supported on the cylinder head 13 in the left-right direction. The front and rear rocker arms 67i and 67e that swing by the rotation of the valve open and close the intake and exhaust valves (not shown).
The camshaft 65 is fitted with a driven chain sprocket 68 at the end of the left shaft (see FIG. 3).

  On the other hand, a drive chain sprocket 25 is spline-fitted on the left side of the journal portion of the left crankshaft body 20L protruding leftward from the left bearing wall 11Lw of the crankshaft 20, and the drive chain sprocket 25 and the driven chain sprocket above it A cam chain 69 is bridged between the camshaft 68 and the camshaft 69 (see FIG. 3), and the rotational power of the crankshaft 20 is transmitted to the rotation of the camshaft 65 through the camchain 69 at a speed half that of the crankshaft 20. The rocker arms 67i and 67e are swung in synchronization with the crankshaft 20, and the intake and exhaust valves are driven to open and close at the required timing.

The left crankshaft body 20L protruding leftward from the left bearing wall 11Lw of the crankshaft 20 is connected to the AC generator 30 via a nut member 26 for positioning and fixing the drive chain sprocket 25, a starter driven gear 27, and a one-way clutch 29. The ACG rotor 30R is sequentially fitted, and is fastened and fixed by a nut member 32 through a washer 31 (see FIG. 3 ).
An inner stator 30S is fixedly supported on an inner cylinder 49a formed on a left crankcase cover 49 that covers the AC generator 30 and the like from the left side.

On the other hand, as shown in FIG. 3, a balancer drive gear 35 and a primary drive gear 36 are sequentially fitted to the right crankshaft body 20R protruding rightward from the right bearing wall 11Rw of the crankshaft 20, and a centrifugal filter 37 is further fitted. The filter case 37a is fitted and tightened and fixed with a nut member 39n through a washer 39w.
The centrifugal filter 37 is formed by covering the right opening of a bowl-shaped filter case 37a with a plate-shaped filter cover 37b and forming a centrifugal separation chamber 37c therein. A communication pipe 38 passes through the same axis.

The right crankcase cover 50 covers the right side of the right crankcase 11R (see FIG. 3), and the communication pipe 38 penetrating the filter cover 37b is pressed against the opening end of the oil passage of the right crankcase cover 50 by a disc spring 38s. ing.

  Referring to FIG. 3, in transmission chamber 11M of crankcase 11, main shaft 41 and counter shaft 42 of transmission 40 are directed to the left and right bearing walls 11Lw parallel to each other in the left-right direction behind crankshaft 20. , 11Rw is rotatably supported via bearings 41b and 42b, and a main gear group 41g supported on the main shaft 41 and a counter gear group 42g supported on the counter shaft 42 are always meshed with each other. Consists of 40.

The counter shaft 42 penetrates the crankcase 11 to the left and protrudes to the outside to be an output shaft, and an output sprocket 43 is fitted to the protruding left end.
A drive chain 44 wound around the output sprocket 43 is stretched over a rear sprocket (not shown) to form a chain transmission mechanism, and power is transmitted to the rear wheels.

A multi-plate friction type transmission clutch 46 is provided on the right side of the main shaft 41 protruding rightward from the right bearing wall 11Rw.
A clutch outer 46o of the transmission clutch 46 is supported by a primary driven gear 45 rotatably supported by the main shaft 41 via a buffer member, and is connected to a clutch inner 46i that is integrally fitted to the main shaft 41. A plurality of clutch plates 46c are interposed therebetween and are connected and disconnected by driving the compression member 46p.

A primary driven gear 45 meshes with the primary drive gear 36 fitted to the crankshaft 20.
Accordingly, the power of the crankshaft 20 is transmitted to or disconnected from the main shaft 41 of the transmission 40 by driving the speed change clutch 46.

  In front of the crankshaft 20, a balancer shaft 47 is rotatably mounted between the left and right bearing walls 11Lw and 11Rw (see FIG. 2), and the balancer shaft 47 has a balancer projecting rightward from the right bearing wall 11Rw. A driven gear (not shown) is provided and meshes with the balancer drive gear 35 fitted to the crankshaft 20.

A starter motor 120 is disposed above the upper wall of the crankcase 11 behind the cylinder block 12 that protrudes slightly forward from the crankcase 11.
The drive of the starter motor 120 is transmitted to the starter driven gear 27 via a gear mechanism (not shown).

  The right crankcase cover 50 that covers the right crankcase 11R from the outside includes a centrifugal filter 37 at the right end of the crankshaft 20, a transmission clutch 46 at the right end of the main shaft 41, and a power transmission gear mechanism to the balancer shaft 47 and the crankshaft 20. A power transmission gear mechanism (not shown) to the lower oil pump 48 is covered from the right side (see FIG. 2).

  4 to 10, the right crankcase cover 50 has an outer peripheral edge of the cover side wall 51 that is bent inward (on the right crankcase 11R side) and has a mating surface 54s with the right crankcase 11R on the end surface. A peripheral edge 54 is formed, and a plurality of mounting holes 54 h are formed in the outer peripheral edge 54.

The cover side wall 51 has a front portion, a rear portion, and a lower portion partially, and a large portion of a substantially central portion is large and bulges outward in the vehicle width direction to form a bulging wall 52. A further central portion of the bulging wall 52 A circular bulging portion 53 is formed in which a portion facing the transmission clutch 46 bulges in a circular shape.
The front surface 52 s of the bulging wall 52 of the right crankcase cover 50 is inclined obliquely upward, and the front outer surface 51 s of the cover side wall 51 and the front surface 52 s of the bulging wall 52 are substantially in front of the bulging wall 52. Corner portions 57 that intersect at right angles and are L-shaped are formed (see FIGS. 4 and 7).

A pair of lower mounting boss portions 55 and upper mounting boss portions 56 are formed on the inclined front surface 52s of the bulging wall 52 so as to protrude obliquely upward.
The lower mounting boss portion 55 and the upper mounting boss portion 56 project along the front outer side surface 51 s of the cover side wall 51 in an elliptical shape whose major axis is oriented obliquely in the vertical direction.

An oil upstream passage 58 that perforates the center of the lower mounting boss portion 55 opens to an elliptical end surface of the lower mounting boss portion 55, and the end surface is located above and below the opening of the oil upstream passage 58. Bolt mounting holes 55b and 55b are formed.
Similarly, in the upper mounting boss portion 56, an oil downstream side passage 59 pierced in the center is opened on an elliptical end surface of the upper mounting boss portion 56, and the upper and lower sides of the opening of the oil downstream side passage 59 are formed on the same end surface. Bolt mounting holes 56b and 56b are formed in the upper part.

The oil upstream side passage 58 extends rearward and obliquely downward and communicates with the discharge oil passage of the oil pump 48.
A branched oil passage 58 b branched from the middle of the oil upstream side passage 58 reaches a centrifugal filter 37 provided at the right end of the crankshaft 20.
The oil downstream side passage 59 is an oil passage that supplies oil to the valve operating mechanism 60 of the cylinder head 13 through the crankcase 11 and the cylinder block 12.

The oil cooler unit 70 is attached to the lower attachment boss portion 55 and the upper attachment boss portion 56.
As shown in FIGS. 4 and 5, the oil cooler unit 70 is an air-cooled oil cooler 71 that is integrally provided with an oil introduction passage 75i and an oil outlet passage 76e.

The air-cooled oil cooler 71 has three connecting pipes 72 that are formed in a flat oval shape with connecting pipes 72i and 72e that are expanded at both ends by overlapping a pair of plate members in the middle. The connecting pipes 72i and 72e are joined and integrated, and cooling fins 73 are interposed between the flat communicating pipes 72 and 72.
The oil introduced into the three connecting pipes 72i on one side passes through the three connecting pipes 72 and reaches the three connecting pipes 72e on the other side, while the cooling fins 73 are deprived of heat by the traveling wind. The oil is cooled more efficiently.

4 and 5, a unit mounting portion 75a to be fastened to the lower mounting boss portion 55 is formed integrally with an oil introduction tube 75 extending to one of the three connecting pipes 72i that communicate with each other. .
The unit mounting portion 75a has an elliptical plate shape facing the elliptical end surface of the lower mounting boss portion 55, and an oil introduction passage 75i communicating with the oil upstream side passage 58 is opened at the center. The oil introduction passage 75i extends vertically from the opening and bends at right angles to form a passage for the oil introduction pipe 75 and communicate with the three connection pipes 72i.
Bolt through holes 75b and 75b are formed above and below the opening of the oil introduction passage 75i at the center of the unit mounting portion 75a.

Similarly, a unit mounting portion 76a that is fastened to the upper mounting boss portion 56 is integrally formed with an oil outlet pipe 76 that extends to one of the three connecting pipes 72e that communicate with each other.
The unit mounting portion 76a has an elliptical plate shape facing the elliptical end surface of the upper mounting boss portion 56, and an oil outlet passage 76e communicating with the oil downstream side passage 59 is opened at the center. The oil outlet passage 76e extends vertically from the opening and bends at a right angle to form a passage for the oil outlet pipe 76 and communicate with the three connecting pipes 72e.
Bolt through holes 76b and 76b are formed above and below the opening of the oil outlet passage 76e at the center of the unit mounting portion 76a.

As described above, the oil cooler unit 70 in which the air cooling oil cooler 71 is integrally provided with the oil introduction passage 75i and the oil outlet passage 76e has the air cooling oil cooler 71 outside (right side) as shown in FIG. The lower side mounting boss part 55 and the upper side mounting boss part projectingly formed on the front surface 52s inclined obliquely upward of the bulging wall 52 of the right crankcase cover 50 with the unit mounting parts 75a, 76a on the inner side (left side) Fixed to 56 and attached.
It should be noted that connecting seal pipes 77 and 78 (see FIG. 4) are fitted into the opposite oil passage openings of the lower mounting boss portion 55 and the unit mounting portion 75a and the upper mounting boss portion 56 and the unit mounting portion 76a, respectively. Then, the oil upstream side passage 58 and the oil introduction passage 75i, and the oil downstream side passage 59 and the oil outlet passage 76e are communicated with each other.

  Therefore, the oil discharged from the oil pump 48 is branched by having the branch oil passage 58b in the oil upstream side passage 58, and the oil flowing into one branch oil passage 58b is in the crankcase 11 such as the crankshaft 20 or the like. The oil that has been supplied to the lubrication region and has not branched to the other branch oil passage 58b flows into the air-cooled oil cooler 71 from the oil upstream passage 58, is cooled, flows out to the oil downstream passage 59, and flows downstream. It can flow from 59 to the cylinder block 12 and the cylinder head 13 where the temperature rise is large and can be used for cooling.

  The air-cooled oil cooler 71 does not cool all the lubricating oil, but only the oil that is supplied to the cylinder block 12 and the cylinder head 13 that particularly require cooling, and thus has a compact structure with a small capacity. be able to.

An air-cooled oil cooler 71 of the oil cooler unit 70 is covered with a protector 80 made of a breathable metal mesh (see FIG. 4).
As shown in FIG. 6, the metal mesh of the protector 80 has an outer portion 81 a that almost covers the outer side of the outermost flat oval communication pipe 72 of the air-cooled oil cooler 71 and the inner side of the innermost communication pipe 72. The inner part 81b and the outer part 81a that cover the outer periphery and the outer peripheral edge of the inner part 81b are connected to each other to form an outer peripheral part 81c that covers the front (obliquely upper) and the upper and lower sides of the air-cooled oil cooler 71. Yes.

Semicircular cutouts 81bv and 81bv that avoid the oil introduction pipe 75 and the oil discharge pipe 76 are formed at the rear edge of the inner portion 81b of the protector 80, and mounting holes 82b are formed above and below the cutouts 81bv and 81bv. , 82b are formed, and projecting pieces 82, 82 project inward at right angles to the inner portion 81b.
When the oil cooler unit 70 is fastened to the right crankcase cover 50 with a bolt 85, the protector 80 is attached with the attachment piece 82 being fastened together with the bolt 85.

  That is, as shown in FIG. 4, an oil cooler is attached to the lower mounting boss portion 55 and the upper mounting boss portion 56 that are formed to project from the front surface 52s inclined obliquely upward of the bulging wall 52 of the right crankcase cover 50. The unit mounting portions 75a and 76a located on the inner side (left side) of the air-cooled oil cooler 71 of the unit 70 are abutted diagonally from the upper front, and the protector 80 is put on the air-cooled oil cooler 71, and the inner portion 81b of the protector 80 The mounting holes 82b and 82b of the mounting pieces 82 and 82 on the upper and lower sides of the rear edge are aligned with the bolt through holes 76b and 76b of the unit mounting portions 75a and 76a, and penetrated by the bolts 85 and 85 to form the lower mounting boss portion 55. The oil cooler unit 70 and the protector 80 are fastened together with the right crankcase cover 50 by screwing into the bolt mounting holes 55b, 55b of the upper mounting boss portion 56.

  When the oil cooler unit 70 is thus attached to the front surface 52s of the bulging wall 52 of the right crankcase cover 50, the oil discharged from the oil pump 48 passes through the oil upstream passage 58 and the oil introduction passage 75i of the oil introduction pipe 75. Then, the air-cooled oil cooler 71 is introduced into the three connecting pipes 72i that communicate with each other, and passes through the three communicating pipes 72 to reach the other three connecting pipes 72e. The oil is cooled by the cooling fins 73 and the communication pipe 72, and the cooled oil is supplied from the oil introduction passage 76e of the oil introduction pipe 76 to the valve mechanism 60 through the oil downstream side passage 59.

  An oil cooler unit 70 in which an air introduction type oil cooler 71 is integrally provided with an oil introduction passage 75i and an oil introduction passage 76e is formed in the mounting boss portions 55 and 56 of the crankcase cover 50 with the oil introduction passage 75i and the oil introduction passage 76e formed therein. The oil-cooled oil cooler 71 is connected to the oil upstream-side passage 58 and the oil downstream-side passage 59 and attached to the crankcase cover 50, so that the air-cooled oil cooler 71 can be used as the oil cooler unit 70 without the need for an external oil pipe. It is assembled to the crankcase cover 50, and it is extremely easy to assemble with a small number of parts and is very easy to assemble.

7 to 10 show the state in which the oil cooler unit 70 and the protector 80 are attached to the right crankcase cover 50 in this way.
The air-cooled oil cooler 71 of the oil cooler unit 70 is configured such that the front outer side surface 51s of the cover side wall 51 and the front surface 52s of the bulge wall 52 intersect each other at a substantially right angle with respect to the bulge wall 52 of the right crankcase cover 50. It is arranged at a corner 57 that becomes a dead space missing in a letter shape.

As shown in FIG. 9, the air-cooled oil cooler 71 is located in front of the bulging wall 52 and on the inner side (left side) in the vehicle width direction from the bulging end of the bulging wall (the rightmost end of the circular bulging wall 53). The air-cooled oil cooler 50 is attached using the dead space in front of the bulging wall 52 of the right crankcase cover 50, and the back of the air-cooled oil cooler 50 is covered over the entire vehicle width direction. The bulging wall 52 can protect the air-cooled oil cooler 50 from behind.
The air-cooled oil cooler 71 can be compactly housed in the corner portion 57 that becomes a dead space in front of the bulging wall 52 of the crankcase cover 50, and the degree of freedom in the arrangement and layout of the equipment can be increased.

  The air-cooled oil cooler 50 attached to the front surface 52s inclined obliquely upward of the bulging wall 52 of the right crankcase cover 50 is in a position to receive traveling wind from the front, and the communication pipe of the air-cooled oil cooler 50 Since the cooling fin (73) interposed between 72 and 72 is mounted in a posture facing the front of the vehicle body, the running wind from the front of the vehicle body directly hits the cooling fin 73 and the oil circulating through the air-cooled oil cooler 71 is efficient. It can cool well.

Further, since the front surface 52s of the bulging wall 52 is inclined obliquely upward, the cooling air after passing through the air-cooled oil cooler 71 is smoothly removed along the inclined surface of the front surface 52s of the bulging wall 52. Therefore, the oil can be efficiently cooled.
The traveling wind that has entered between the air-cooled oil cooler 50 and the front outer surface 51s of the cover side wall 51 passes outwardly (rightward) between the lower mounting boss portion 55 and the upper mounting boss portion 56. It does not cause air accumulation and does not disturb the cooling action.

  Further, since the front surface 52s of the bulging wall 52 is inclined obliquely upward, the bulging wall 52 protects not only the back of the air-cooled oil cooler 71 but also the lower side, so that the air-cooled oil cooler 71 from stepping stones and the like. Can be protected as much as possible.

  By positioning the unit mounting portions 75a and 76a on the inner side in the vehicle width direction along the front outer surface 51s of the cover side wall 51, the oil upstream passage 58 and the oil downstream passage 59 in the crankcase cover 50 can be set short. By positioning the air-cooled oil cooler 71 on the outer side in the vehicle width direction, the air-cooled oil cooler 71 can be efficiently exposed to the traveling wind, and the oil cooling efficiency can be increased.

Since at least the front of the air-cooled oil cooler 71 and the outside in the vehicle width direction are covered with a metal mesh protector (80) having air permeability, the protector 80 impairs the cooling effect of the running air of the air-cooled oil cooler 71. In addition, the air-cooled oil cooler 71 can be protected from external force.
Further, since the protector 80 is attached together with the oil cooler unit 70 together with the crankcase cover 50, the assembling work is further facilitated with a small number of parts.

  In addition, as a protector which has air permeability, it can also be considered to use a louver structure in addition to a metal mesh.

An air-cooled oil cooler mounting structure according to another embodiment will be described with reference to FIG.
The same reference numerals as those in the above embodiment are used for the members.
The air-cooled oil cooler mounting structure is clearly shown in comparison with FIG. 7 of the above embodiment, and the two front mounting holes 54h of the outer peripheral edge portion 54 of the right crankcase cover 50 mounted to the right crankcase 11R. , 54 h mounting bosses 54 b, 54 b protrude forward from the outer peripheral portion 81 c of the protector 80.
Accordingly, all the mounting boss portions of the right crankcase cover 50 do not overlap the air-cooled oil cooler 71 and the protector 80 in a side view.

  Therefore, the air-cooled oil cooler 71 and the protector 80 do not get in the way when the right crankcase cover 50 is attached to and detached from the crankcase 11, and the air-cooled oil cooler 71 and the protector 80 need not be removed from the right crankcase cover 50. The right crankcase cover 50 can be attached / detached with the attachment attached, and the workability is good.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Crankcase, 11P ... Oil sump, 20 ... Crankshaft, 20L, 20R ... Crankshaft body, 37 ... Centrifugal filter, 38 ... Communication pipe, 47 ... Balancer shaft, 48 ... Oil pump, 49 ... Left crankcase cover,
50 ... right crankcase cover, 51 ... cover side wall, 51s ... front side outer surface, 52 ... bulge wall, 52s ... front surface, 53 ... circular bulge, 55 ... lower mounting boss, 56 ... upper mounting boss, 57 ... Corner, 58 ... Oil upstream passage, 59 ... Oil downstream passage, 60 ... Valve mechanism,
70 ... Oil cooler unit, 71 ... Air-cooled oil cooler, 72 ... Communication pipe, 73 ... Cooling fin, 75 ... Oil inlet pipe, 75a ... Unit mounting part, 75i ... Oil inlet passage, 76 ... Oil outlet pipe, 76a ... Unit Mounting part, 76e ... oil outlet passage, 77, 78 ... connecting seal pipe,
80 ... protector, 81a ... outer part, 81b ... inner part, 81c ... outer peripheral part, 82 ... mounting piece, 85 ... bolt.

Claims (6)

In a vehicle-mounted internal combustion engine in which a crankcase cover (50) covers an axially outer side of a crankcase (11) that rotatably supports a crankshaft (20) oriented in the vehicle width direction,
An oil cooler unit (70) in which an air-cooled oil cooler (71) is integrally provided with an oil introduction passage (75i) and an oil delivery passage (76e), the oil introduction passage (75i) and the oil delivery passage (76e) are provided. wherein each communicates with the oil upstream passage formed in the crankcase cover (50) (58) and the oil downstream passage (59), mounted on a front portion of the crankcase cover (50),
The crankcase cover (50) is formed with a mating surface with the crankcase (11) on the outer peripheral edge of the cover side wall (51),
The air-cooled oil cooler (71) is positioned in front of the bulging wall (52) that bulges outward in the vehicle width direction of the cover side wall (51), and is wider than the bulging end of the bulging wall (52). Placed inside the direction,
The front outer surface (51s) of the cover side wall (51) in front of the bulging wall (52) and the front surface (52s) of the bulging wall (52) intersect each other at a substantially right angle and are lost in an L shape. A corner (57) is formed,
The air-cooled oil cooler (71) is disposed at the corner (57) in front of the bulging wall (52) of the cover side wall (51),
Mounting bosses (55, 56) are provided on the front surface (52s) of the bulging wall (52) or the front outer surface (51s) of the cover side wall (51), the oil upstream side passageway (58) and the oil downstream side. Projecting with passageway (59),
The unit mounting portion (75a, 76a) fixed to the mounting boss portion (55, 56) of the bulging wall (52) includes the oil introduction passage (75i) and the oil outlet passage (76e). Built integrally with the cooler unit (70),
By fixing the unit mounting portions (75a, 76a) of the oil cooler unit (70) to the mounting boss portions of the crankcase cover (50), the oil upstream passage (58) and the oil downstream passage The oil cooler unit (70) is attached to the crankcase cover (50) by connecting the oil introduction passage (75i) and the oil lead-out passage (76e) to (59), respectively. Air-cooled oil cooler mounting structure.   The oil cooler unit (70) is attached to the front portion of the crankcase cover (50) in a posture in which the cooling fin (73) provided in the air-cooled oil cooler (71) faces the front of the vehicle body. An air-cooled oil cooler mounting structure for an internal combustion engine according to claim 1. The air-cooled oil cooler mounting structure for an internal combustion engine according to claim 1 or 2, wherein the front surface (52s) of the bulging wall (52) is inclined obliquely upward. The oil cooler unit (70) is configured so that the air-cooled oil cooler (71) is positioned on the outer side in the vehicle width direction, the unit mounting portion (75a, 76a) is set on the inner side in the vehicle width direction, and the unit mounting portion (75a, 76a ) to be positioned along the front outer surface (51 s) of the cover side wall (51), according to claim, wherein said being secured to the mounting boss portion of the crankcase cover (50) (55, 56) The air-cooled oil cooler mounting structure for an internal combustion engine according to any one of claims 1 to 3 . The internal combustion engine according to any one of claims 1 to 4 , wherein at least the front and the outer side in the vehicle width direction of the air-cooled oil cooler (71) are covered with a breathable protector (80). Engine air-cooled oil cooler mounting structure. 6. An air-cooled oil cooler mounting structure for an internal combustion engine according to claim 5, wherein the protector (80) is attached to the crankcase cover (50) together with the oil cooler unit (70).

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